Giggling

     This happened two days ago. I was in the Library, it was about 4:15 in the late afternoon. My dog was asleep on his pillow next to the radiator. The day had been sunny and bright, warm for this time of year. My wife was not at home. I was answering some correspondence when I thought I heard someone giggle. I stopped and listened, wondering if I had actually heard what I thought I had. The giggling sounded a second time, it appeared to be coming from the diningroom. It sounded very much like the slightly musical giggle of  one or more young girls of maybe 10 or 12 years of age. The dog didn't hear it, he was sound asleep; he didn't even awaken when I walked past him and into the obviously empty diningroom. This house was built of brick, the walls are thick and even the enterior walls are brick. Sounds must be rather loud to carry into this house. Do mice giggle?